The present invention relates to a flame-retardant epoxy resin composition, a molded article thereof and an electronic part.
Epoxy resin has been widely used as insulating materials of electrical and electronic parts such as a laminate material and an encapsulating material for a semiconductor device, for example, IC, LSI, VLSI or the like because of excellencies in electrical characteristics such as insulating property, heat resistance, moisture resistance, acid resistance, solvent resistance, adhesiveness, mechanical properties, dimensional stability and others, and furthermore, relative inexpensiveness.
In company with great development in the electronic technology in recent years, a progress toward high integration in a semiconductor device and a laminate has reached to higher level and at the same time, requirements for higher reliability thereof have been increased. In such a current situation, epoxy resin used as an insulating material has also been required to have better characteristics thereof such as heat resistance (including soldering heat resistance), a flame retardance, moisture resistance, adhesiveness and mechanical properties.
In order to improve characteristics, especially flame retardance and heat resistance, of epoxy resin, a phosphazene compound is compounded into the resin as a flame retardant and/or a hardener (for example, Japanese Unexamined Patent Publication No. Sho-61-120850, Japanese Unexamined Patent Publication No. Sho-48-37500, Japanese Examined Patent Publication No. Hei-3-4565, Japanese Examined Patent Publication No. Hei-6-104714 and Japanese Unexamined Patent Publication No. Hei-10-259292).
Phosphazene compounds disclosed in the prior arts all lack a sufficient effect in an aspect of improving moisture resistance of epoxy resin. Moisture resistance of epoxy resin is an especially important property in a case where the resin is used as material of a printed circuit board. That is, since laminates have a chance to be used in the air with a high frequency and an insulating property and, hence, a reliability are degraded due to moisture absorption, the resin is desired to have a low water absorption and no change in electrical characteristics such as an insulating property. In a case where a phosphazene compound low in effect of improving moisture resistance is used as a laminate material, inconveniences such as swelling or peeling of a metal sheet, a metal foil or the like occurs due to moisture absorption in a high temperature treatment such as a soldering process, thereby disabling a laminate with a long term reliability to be obtained.
The present inventors have conducted serious studies in order to solve the above problem, which, as a result of the studies, leads to a discovery that epoxy resin compounded with a specific phosphazene compound can exert conspicuously excellent performance, thereby having completed the present invention.
That is, according to the present invention, there is provided a flame-retardant epoxy resin composition containing an epoxy resin (A) and a phosphazene compound (B), wherein the component (B) is included in the range of 0.01 to 70% by weight relative to a total quantity of the component (A) and the component(B), and
wherein the component (B) is at least one member selected from the group consisting of
(1) a cyclic and/or a chain phosphazene compound expressed by a general formula (1): 
wherein each R1 and R2, being identical or different, is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms, an alkylaryl group having 7 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an alkenylaryl group having 8 to 18 carbon atoms, an amino group-substituted phenyl group, an aminoalkyl group-substituted phenyl group where the aminoalkyl group has 1 to 6 carbon atoms, a hydroxy group-substituted phenyl group, a hydroxyalkyl group-substituted phenyl group where the hydroxyalkyl group has 1 to 6 carbon atoms, a glycidyloxy group-substituted phenyl group or a glycidyloxyalkyl group-substituted phenyl group where the glycidyloxyalkyl group has 4 to 9 carbon atoms, providing that at least one of n R1s and n R2s is the amino group-substituted phenyl group, the aminoalkyl group-substituted phenyl group where the aminoalkyl group has 1 to 6 carbon atoms, the hydroxyalkyl group-substituted phenyl group where the hydroxyalkyl group has 1 to 6 carbon atoms, the glycidyloxy group-substituted phenyl group or the glycidyloxyalkyl group-substituted phenyl group where the glycidyloxyalkyl group has 4 to 9 carbon atoms, and n indicates an integer of from 3 to 10000;
(2) a polymer of the cyclic and/or the chain phosphazene compound; and
(3) a reaction product of the cyclic and/or the chain phosphazene compound with at least one compound selected from the group consisting of an epoxy compound, a phenol compound, an amine compound and an acid anhydride.
The flame-retardant epoxy resin composition is further compounded with an epoxy hardener (C), wherein the component (B) and the component (C) are included in the range of 0.01 to 70% by weight and in the range of 0 to 70% by weight, respectively, relative to a total quantity of the component (A), the component(B) and the component (C).
Furthermore, according to the present invention, there is provided a flame-retardant epoxy resin composition containing an epoxy resin (A), a phosphazene compound (B), an epoxy hardener (C) and an inorganic filler (D), wherein the component (B) and the component (C) are included in the range of 0.01 to 70% by weight and in the range of 0 to 70% by weight, respectively, relative to a total quantity of the component (A), the component(B) and the component (C), and the component (D) is included in the range of 0 to 95% by weight relative to a total quantity of the component (A), the component(B), the component (C) and the component (D) and
wherein the component (B) is at least one member selected from the group consisting of
(1) a cyclic and a chain phosphazene compound expressed by a general formula (1): 
wherein each R1 and R2, being identical or different, is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms, an alkylaryl group having 7 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an alkenylaryl group having 8 to 18 carbon atoms, an amino group-substituted phenyl group, an aminoalkyl group-substituted phenyl group where the aminoalkyl group has 1 to 6 carbon atoms, a hydroxy group-substituted phenyl group, a hydroxyalkyl group-substituted phenyl group where the hydroxyalkyl group has 1 to 6 carbon atoms, a glycidyloxy group-substituted phenyl group or a glycidyloxyalkyl group-substituted phenyl group where the glycidyloxyalkyl group has 4 to 9 carbon atoms, providing that at least one of n R1s and n R2s is the amino group-substituted phenyl group, the aminoalkyl group-substituted phenyl group where the aminoalkyl group has 1 to 6 carbon atoms, the hydroxyalkyl group-substituted phenyl group where the hydroxyalkyl group has 1 to 6 carbon atoms, the glycidyloxy group-substituted phenyl group or the glycidyloxyalkyl group-substituted phenyl group where the glycidyloxyalkyl group has 4 to 9 carbon atoms, and n indicates an integer of from 3 to 10000;
(2) a polymer of the cyclic and/or the chain phosphazene compound; and
(3) a reaction product of the cyclic and/or the chain phosphazene compound with at least compound selected from the group consisting of an epoxy compound, a phenol compound, an amine compound and an acid anhydride.
A phosphazene compound of the component (B) used in the present invention is good in reactivity and compatibility with an epoxy resin and considered to act as a hardener and a flame retardant for the epoxy resin. This compound does not degrade electrical characteristics such as an insulating property, mechanical properties, adhesiveness and others of the epoxy resin, rather exerts excellent performance to improve the characteristics and properties according to a case and, in addition, further increase moisture resistance. A high reliability is therefore shown and also sustained over a long time by a molded article (a molded product) obtained by molding a flame-retardant epoxy resin composition of the present invention, for example an electronic part such as a laminate.